Why is the sun shining?

A while ago she said to me: try to do things that makes you happy.
And before that I have read somewhere that you can achive happines by doing all sorts of common things, small things....but do them right and get them done.
And I did so...small and big things...things that I hate to do and things that I love to do...and I gave my best to get them done...
So I guess this is the reason that the sun is shining, even though there are dark clouds in the sky or it's moon time.